1. Field of the Invention
The present invention relates to a data processing device for images of an article having an axis of rotation, applicable in particular to the inspection of machined parts, food cans and beer cans.
2. Description of the Related Art
Devices for inspection of articles of revolution known up to the present time generally have a linear camera which receives an image of a generatrix of the revolving article and thresholds, generally two in number, common to all the photosensitive points of the linear camera. If the thresholds are exceeded an error signal is output.
These devices therefore require an initial calibration for each series of identical articles treated and a recalibration upon every change in series. Furthermore, the light illuminating the article must be of uniform intensity and isotropic. Otherwise, the reflections of light off of the articles cause detections of defects and produce an erroneous inspection result.
For these various reasons, the devices known at the present time are limited to a rough inspection which tolerates the less noticeable defects of relatively cylindrical articles which do not have convergent reflections.
The amount of image data to be treated during an inspection excludes the use of data processing software which uses all of the image data.